In a majority of the installations, a short dryer duct length is not always possible. With excessive duct runs with many turns, the static pressure drop in the duct will be too high and reduce the amount of air that will be extracted from the dryer. The results are prolonged drying times, higher energy usage/costs, and excessive wear and tear on the dryer.
Typical residential dryers are rated at around 160 CFM. This rating is normally measured with no duct and no load in the dryer. Therefore, a booster fan is generally needed in order to maintain a minimum airflow of 100 cfm.
|Dryer boosting is typically required when the duct length exceeds the following:
Maximum duct length with
0 bends = 25'
1 bend = 20'
2 bends = 15'
3 bends = 10'
The solution is to install a dryer booster fan in-line in the existing duct, preferably 15 feet or more from the dryer. A current sensor is used to sense if the dryer is turned on. If the sensor senses current to the dryer, the fan is started. Once the dryer stops, a timer is activated and the fan will continue to evacuate moisture and lint from the duct for seven minutes.